characteristics of papilloma vs tumor

I am scheduled for surgery on Friday and was told this doesn't look like a cancer.  Does anyone know what characteristics a cancerous tumor would have that a papilloma doesn't?  Is it location, shape, size?  The nurse practictioner seemed sure that it was a papilloma and that I should have nothing to worry about.  That does make me feel better.  I quess I wonder why didn't the first biopsy mention a papilloma?  It said hylinized papillary hyperplasia. After doing another u/s 2 months after the biopsy, the surgeon felt it was safer just to remove the mass and get a better report.    So my question is - what does cancer look like?  Can you tell what a papilloma looks like on u/s?

Thanks

[japdip]

It's impossible to say what cancer looks like .... papilloma is a wart like growth on the breast tissue; often this is a condition of the ducts. The biopsy seemed to indicate that these cells showed more growth than would normally be expected. Single Papillomas are benign but multiples can be cancerous.   Regards ....